I think having better/more cooling in the Advance model is far more important than a 2nd m2 slot. adding another heat source is not good IMO
D2D and others have not tested thermal with the 2nd drive and as we know already one side of the laptop is noticeably warmer than the other ie where the SSD is. Not to mention 10th gen cannot be under volted to compensate. D2D was also a little misleading Mercury Silver was not available on all configurations in 2019 and there was a pink one too
It also contradicts so many review comments re TB3. This is a classic example of a reasonable large/heavy laptop that is somewhat more stationary at times so using an external TB3 is no real inconvenience and the new Samsung T7 is not too shabby. Everyone wants bragging rights of TB3 but so few are willing to pay the price for fast peripherals